From: Hauke Mehrtens <hauke@hauke-m.de>
To: musl@lists.openwall.com
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Subject: [PATCH v3 2/2] mips: add vdso support
Date: Tue, 26 Jan 2016 21:26:34 +0100 [thread overview]
Message-ID: <1453839994-7649-2-git-send-email-hauke@hauke-m.de> (raw)
In-Reply-To: <1453839994-7649-1-git-send-email-hauke@hauke-m.de>
vdso support is available on mips starting with kernel 4.4, see kernel
commit a7f4df4e21 "MIPS: VDSO: Add implementations of gettimeofday()
and clock_gettime()" for details.
In Linux kernel 4.4.0 the mips code returns -ENOSYS in case it can not
handle the vdso call and assumes the libc will call the original
syscall in this case. Handle this case in musl. Currently Linux kernel
4.4.0 handles the following types: CLOCK_REALTIME_COARSE,
CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME and CLOCK_MONOTONIC.
These are some measurements of calling clock_gettime(CLOCK_MONOTONIC,
&tp); 1.000.000 times.
without vdso:
root@OpenWrt:/# time ./vdso-test
real 0m 0.95s
user 0m 0.24s
sys 0m 0.70s
with vdso:
root@OpenWrt:/# time /usr/bin/vdso-test
real 0m 0.35s
user 0m 0.34s
sys 0m 0.00s
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
arch/mips/syscall_arch.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/mips/syscall_arch.h b/arch/mips/syscall_arch.h
index e74e0ad..39c0ea3 100644
--- a/arch/mips/syscall_arch.h
+++ b/arch/mips/syscall_arch.h
@@ -161,3 +161,7 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
if (n == SYS_fstatat) __stat_fix(c);
return r2;
}
+
+#define VDSO_USEFUL
+#define VDSO_CGT_SYM "__vdso_clock_gettime"
+#define VDSO_CGT_VER "LINUX_2.6"
--
2.7.0.rc3
next prev parent reply other threads:[~2016-01-26 20:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-26 20:26 [PATCH v3 1/2] vdso: clock_gettime: call normal syscall in case of an error Hauke Mehrtens
2016-01-26 20:26 ` Hauke Mehrtens [this message]
2016-01-27 17:11 ` Rich Felker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1453839994-7649-2-git-send-email-hauke@hauke-m.de \
--to=hauke@hauke-m.de \
--cc=musl@lists.openwall.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).